The present invention is directed to a combined occupant characteristic and crash sensor arrangement, and more particularly to an arrangement for acoustically sensing a crash event via the output of an occupant characteristic sensor.
Occupant protection systems are well known in the art and are employed in vehicles to protect vehicle occupants during crash events. Most occupant protection systems include one or more actuatable protecting components, such as air bags, seat belt pretensioners, side curtains, etc. During a crash event, these components may be actuated to physically engage an occupant and protect the occupant during a crash event.
Deployment or actuation of an actuatable protection component is usually dependent upon numerous criteria, such as one or more vehicle crash conditions, and possibly one or more occupant characteristics. Vehicle crash conditions are indicative of the occurrence of a vehicle crash event. Further, the crash conditions may indicate whether a crash event is a deployment crash event. A deployment crash event is a crash event that warrants actuation or deployment of the actuatable protection component. In one example, a determination of whether a deployment crash event is occurring is based upon a determination of whether a sensed crash metric, such as crash acceleration, exceeds a threshold value.
With respect to sensing crash conditions, multiple sensors are often placed at a variety of locations throughout the vehicle to sense crash conditions. These sensors usually sense the occurrence of a crash event and output signals indicative thereof. The signals are typically sent to a controller (typically a microprocessor or microcomputer) for a determination of whether the crash event is a deployment crash event. Most often, the controller discriminates between a deployment and a non-deployment crash event by applying a crash algorithm to the signals.
Accelerometers are the type of sensors most often used to sense and indicate the occurrence of a crash event. U.S. Pat. No. 5,670,853, for instance, discloses an occupant protection system that uses an accelerometer to sense a crash event.
Accelerometers are well known in the art and, therefore, their inter-workings are not discussed in great detail. Suffice it to say, most accelerometers have moving parts and sense acceleration through the movement of those moving parts relative to one another. Additionally, most accelerometers have an axis of sensitivity that corresponds to the direction in which the accelerometers sense acceleration.
Accordingly, to effectively sense a crash event that has an orientation along a particular direction with an accelerometer, the accelerometer is oriented in the same direction. For instance, to sense a side impact crash event, the accelerometer is typically oriented in the vehicle such that its axis of sensitivity corresponds to a side-to-side direction of the vehicle. Similarly, orienting the axis of sensitivity in front to rear direction of the vehicle enables the accelerometer to sense front to rear crash events. U.S. Pat. Nos. 5,826,903 and 5,746,444, for example, disclose crash event sensing with accelerometers oriented with their axes sensitivity from side-to-side or front-to-back in the vehicle.
An acoustic sensor is another sensor type that is used to sense crash events. For instance, U.S. Pat. Nos. 5,884,203, 4,842,301, and 4,346,914 disclose acoustic sensors that are used to sense crash events.
Acoustic crash sensors sense crash events off of vibrations that are introduced into a vehicle during a crash event. The vibrations, may, for example, be the result of acoustic waves that are caused by deformation of the vehicle body during a crash event. Acoustic sensors sense these vibrations and output signals indicative thereof. Acoustic sensors are often acoustic transducers, such as ultrasonic sensors which sense high frequency acoustic waves that propagate through the vehicle during the occurrence of a vehicle crash event. Ultrasonic sensors convert the sensed acoustic waves into signals having electrical characteristics indicative of the acoustic waves or vibrations transmitted through the vehicle during a crash event.
Ultrasonic sensors typically do not rely on moving parts to be actuated. As such, they have a short response time relative to other sensors. Additionally, ultrasonic sensors are usually omni-directional, meaning that they detect acoustic waves or vibrations originating from any direction in the vehicle. As such, ultrasonic sensors can rapidly sense crash events originating from most any direction in the vehicle.
With regard to occupant characteristics, these often include the weight and/or position of the occupant (e.g. whether the sensed occupant is a large adult seated close to the vehicle dashboard). Numerous sensors are typically employed in occupant protection systems to sense the various criteria with regard to the occupant characteristics. These sensors sense the criteria and output signals indicative thereof. The signals are usually sent to the controller. The controller then uses these signals to determine control of the actuatable protection component.
With respect to sensing occupant characteristics, many different types of sensors and sensing methodologies are known to sense many different occupant characteristics, such as occupant weight and/or position. These sensors sense the occupant characteristics and output signals indicative thereof.
Occupant characteristics, such as weight and position may be important because they can affect how and to what extent a protection component, such as an air bag should be deployed. With respect to occupant position, for example, if the occupant is moved in a direction toward the air bag during a crash event, it may be desirable to only partially inflate the air bag as the occupant""s motion expedites the engagement of the air bag and the occupant. Alternatively, if the occupant is moved completely out of position during a crash event, such that deployment of the air bag would offer little or no protection to the occupant. Thus, the deployment of the air bag may be suppressed. With respect to sensing occupant position, U.S. Pat. No. 5,670,853, for example, discloses that occupant position may be sensed using different arrangements, such as with a plurality of ultrasonic sensors mounted at various locations within a vehicle.
With respect to the weight of the occupant, the occupant""s weight may affect how and to what extent a protection component, such as an air bag, should be deployed. A larger occupant may, for example, require full deployment to afford the desired protection to the occupant, whereas a smaller occupant may only require partial deployment to protection the occupant in a desired fashion.
With respect to sensing the weight off the occupant, numerous types of weight sensing devices have been developed to determine the weight of an occupant. Some weight sensors are mounted within the seat cushion of a vehicle seat while other weight sensors are mounted between the seat and the vehicle body. Typically, a transducer, such as a piezoelectric device, magnetostrictive device, or a strain gauge, is used to convert a load applied to the seat into an electrical signal indicative of the applied load (e.g. the occupant""s weight). For instance, U.S. Pat. Nos. 5,624,132, 5,494,311, and 5,232,243 disclose using force sense resistors to sense the weight of an occupant. U.S. Pat. No. 5,991,676 and U.S. Pat. No. 5,474,327 disclose using variable resistance weight sensors to sense the weight of an occupant. U.S. Pat. No. 5,739,757 discloses using a magnetic weight sensor to sense the weight of an occupant.
It is well known that vibrations present in a vehicle (resulting from a crash event or from simple road noise) typically propagate throughout the entirety of the vehicle. As such, these vibrations can affect the sensors within the vehicle. More particularly, the sensors sense these vibrations and frequency components indicative of the vibrations are embedded within the signals output by the sensors. These frequency components are undesirable and the signals output from these sensors are, therefore, usually filtered to filter out the effects of these vibrations. U.S. Pat. Nos. 5,739,757 and 5,624,132, for example, disclose that the output from weight sensors is filtered. U.S. Pat. No. 4,842,301 discloses that the output from an acoustic sensor is filtered to filter out noise, such as road noise and/or collision noise, such as noise that would result from collision with a deer.
In accordance with one aspect, the present invention provides an arrangement for use in a vehicle. Occupant characteristic sensor means senses an occupant characteristic and outputs a signal indicative thereof. Means monitors the signal for a frequency component indicative of a vehicle crash event.
In accordance with another aspect, the present invention provides an occupant protection system for use in a vehicle. The system includes an actuatable protection device. Occupant characteristic sensor means senses an occupant characteristic and outputs a sensor signal indicative thereof. Filter means, operatively connected to the occupant characteristic sensor means, passes a frequency component of the sensor signal indicative of a vehicle crash. Controller means, operatively connected to the protection device, the occupant characteristic sensor means and the filter means, controls actuation of the protection device in response to the sensor signal and the filtered frequency component.
In accordance with another aspect, the present invention provides a method of sensing and monitoring for use in a vehicle. An occupant characteristic is sensed. A signal indicative of the sensed occupant characteristic is output. The signal is monitored for a frequency component indicative of a vehicle crash event.
In accordance with yet another aspect, the present invention provides a method of protecting an occupant in a vehicle with an actuatable protection device. An occupant characteristic is sensed. A sensor signal indicative of the sensed occupant characteristic is output. The sensor signal is filtered to pass a frequency component of the sensor signal indicative of a vehicle crash. Actuation of the protection device is controlled in response to the sensor signal and the filtered frequency component.